Butsuri
Online ISSN : 2423-8872
Print ISSN : 0029-0181
ISSN-L : 0029-0181
Current issue
Displaying 1-21 of 21 articles from this issue
Preface
Contents
Overview Articles
  • Yoshihiko Hasegawa
    Article type: Overview Articles
    2024 Volume 79 Issue 3 Pages 108-116
    Published: March 05, 2024
    Released on J-STAGE: March 05, 2024
    JOURNAL RESTRICTED ACCESS

    High quality comes at a high cost. This fact, which we experience in everyday life, also holds in thermodynamic systems. The thermodynamic uncertainty relation, which was first formulated in 2015, quantifies this relationship and states that the fluctuation (the variance divided by the square of the mean) of a stochastic thermodynamic system is bounded from below by twice the inverse of the entropy production. This article is a comprehensive review of the thermodynamic uncertainty relation, where classical cases are presented first, followed by quantum cases.

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Researches
  • Nanami Kawada
    Article type: Researches
    2024 Volume 79 Issue 3 Pages 117-122
    Published: March 05, 2024
    Released on J-STAGE: March 05, 2024
    JOURNAL RESTRICTED ACCESS

    The decay of radioactive isotopes, uranium, thorium and potassium, in the Earth’s interior generates a significant amount of radiogenic heat and contributes to the Earth’s heat budget. The abundance of these elements is a key parameter in revealing the geophysical activity of the planet. Geoneutrinos produced by these isotopes are a unique probe of the composition and hence the amount of the radiogenic heat in the Earth. KamLAND has been observing geoneutrinos from 238U and 232Th with a 1 kilotonne liquid scintillator for more than 20 years. The low-reactor period since 2011 allowed a spectroscopic measurement of geoneutrinos from 238U and 232Th by reducing the most serious background, the reactor neutrino. The number of geoneutrino signals is estimated to be 116.6+41.0-38.5, 57.5+24.5-24.1 and 173.7+29.2-27.7 from 238U, 232Th and 238U+232Th, respectively. These correspond to geoneutrino fluxes of 14.7+5.2-4.8, 23.9+10.2-10.0 and 32.1+5.8-5.3×105 cm-2 s-1, respectively. The null-signal hypothesis is rejected at the 8.5σ confidence level. This study provides the first constraint on the radiogenic heat contribution of 238U and 232Th individually, which is consistent with geochemical predictions based on the compositional analysis of chondrite meteorites.

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  • Takuya Satoh, Yoshihiko Togawa, Hiroaki Kusunose, Jun-ichiro Kishine
    Article type: Researches
    2024 Volume 79 Issue 3 Pages 123-128
    Published: March 05, 2024
    Released on J-STAGE: March 05, 2024
    JOURNAL RESTRICTED ACCESS

    The connection between “crystal chirality” and “phonon angular momentum” is elucidated based on recent Raman scattering experiments in chiral crystals. We provide clear definition of chiral phonons, and demonstrate the conservation between pseudo-angular momentum of chiral phonon and photon spin in Raman scattering.

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  • Masamichi Miyaji
    Article type: Researches
    2024 Volume 79 Issue 3 Pages 129-134
    Published: March 05, 2024
    Released on J-STAGE: March 05, 2024
    JOURNAL RESTRICTED ACCESS

    We explore the applications of tensor networks in gauge/gravity duality. A tensor network serves as an efficient geometric representation of a quantum state, encoding the structure of quantum entanglement in the same way as the Ryu-Takayanagi formula in gauge/gravity duality. This implies that the tensor network provides a model for a time slice in anti-de Sitter space, facilitating the connection of various bulk geometric quantities with quantum information-theoretic quantities at the boundary. Within this article, we explore several such applications and establish the continuum limit of the tensor network using a path-integral approach. This allows us to directly extract bulk metrics from the tensor network.

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